1. Field of the Invention
This invention relates, generally, to door or window construction. More particularly, it relates to a brace assembly that strengthens and locks against movement the mitered corner of a door or window frame.
2. Description of the Prior Art
The frame of a door or window is weakest at its corners. Typically, a corner of a door or window frame is formed by a horizontal part having a flat end butted against a vertical part having a flat edge. An elongate fastener, known as a flush bolt rod, or similar fastening member is then used to secure the two abutting parts together.
Such construction is quite weak, due to the inherent instability of two flat parts abutting one another at a right angle. More particularly, the respective lengths of the vertical frame parts on opposite sides of the door or window and the horizontal frame parts at the top and bottom thereof provide considerable leverage, i.e., a moment appears where the frame parts flatly abut one another and the forces generated by users of the door or window are amplified and thus cause deterioration of the structural integrity of the window or door frame.
Accordingly, developers of the art of door and window frame construction have introduced mitered parts to eliminate the problems associated with abutting flat parts. However, firmly securing the junction of two mitered parts that meet to form a corner of a hollow door or window frame has also proved problematic. A number of techniques have been tried, but due to the moment of forces acting on the corners of such a frame, no construction technique has heretofore been found that provides a durable door or window frame having corners formed of mitered parts.
Moreover, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in this art how the needed door or window construction could be provided.